1. Field of the Invention
The present invention relates to a bottom plate of a chair, especially a bottom plate structure that has multiple adjusting functions.
2. Description of the Prior Arts
A conventional chair comprises a bottom plate, a back rack and a seat frame. The back rack is always pivotally and elastically connected to the bottom plate and rotates relative to the bottom plate. So a user can stretch his or her body for relaxation.
For accomplishing the relaxing effect, an elastic component is applied to connect the bottom plate and the back rack. When the user leans against a backrest of the back rack, the elastic component is stretched and the back of the users can be stretched. When the user no longer leans against a backrest of the back rack, the back rack is repositioned to the original position by the elastic component.
However, the conventional elastic component is stretched by the back rack and the elasticity of the elastic component is fixed and unadjustable. When the user sits and leans against the back rack for a long period of time, the elastic component is fatigued by the leaning forces of the users, and this affects the sitting comfort provided by the chair. Furthermore, different users may have different requirements of elasticity, and the users may hope that the elasticity of the elastic component can be adjusted to meet different conditions, but the conventional elastic component does not have the elasticity adjusting function.
In addition, the user needs to adjust the back inclined angle of the back rack for matching the different using conditions. When the user sits on the chair in a causal situation, the back rack is adjusted to a specific back inclined angle, so the back of the user can be stretched for relaxation. When the user is involved in some work by sitting upright on the chair, the back rack is adjusted to a vertical angle for supporting the user.
But the back rack of the conventional chair provides only two adjusting positions to the users rather than having multiple back inclined angles, one of the adjusting positions is vertical and the other one of the adjusting positions is a specific back inclined angle, thus the adjusting function of the back rack of the conventional chair is inadequate to the users.
Additionally, a cushion is mounted on the seat frame of the conventional chair. As usual, the seat frame is mounted securely on the bottom plate with a front inclined angle for improving the comfort of the chair. So the front inclined angle of the seat frame is unadjustable. However, when the users sit on the conventional chair, the users with different heights may prefer different front inclined angles. The conventional chair obviously cannot meet the usage demands.
To overcome the shortcomings, the present invention provides a bottom plate structure of a chair to mitigate or obviate the aforementioned problems.